I love matrix - I've been running a Synapse homeserver for over 2 years now for friends and family. We love it. Despite minor problems (upgrading postgres for example) it has been smooth sailing. I really want to stay up to date but they don't make it easy! I'd love to add sliding-sync to my existing docker stack, but I feel like I'm in way over my head!
It might be difficult to switch at this point, but I highly recommend matrix-docker-ansible-deploy[0]. Enabling sliding-sync is one config entry.

[0] https://github.com/spantaleev/matrix-docker-ansible-deploy